In the field of applicators that apply a fluid to an applied object, correction fluid applicators (correction pens) for applying a correction fluid to a paper surface have been widely used in order to correct errors in text and the like on the paper surface. The applicator of this kind includes a valve mechanism using a spring and opens and closes the valve mechanism to thereby open and close the ejection opening of the correction fluid.
Concerning the above applicators, the applicator described in Japanese Utility Model Application Laid-open HEI 07-24472 (patent document 1) is provided with a correction fluid feeder b at the front end of a container body a, as shown in FIG. 9. In this correction fluid feeder b, a front barrel f of a tubular member with a fluid ejection opening c at the tip is formed with an applying surface d around ejection opening c. An applying part h is repulsively urged forwards by a spring j and inserted in the front barrel f and has a tip g whose pressing end as a part thereof is projected from the aforementioned ejection opening c. Applying part h is constructed such that the rear of tip g is enlarged in diameter via a step e, forming a large-diametric cylindrical part k. This step e has a tapered form and is adapted to close and open ejection opening c as a step i of applying part h that is urged by spring j comes into close contact with, and out of contact with, a seat e around ejection opening c inside front barrel f.
In other words, the correction fluid feeder functions such that when it is used, tip g of applying part h is pressed against an applied object so as to open ejection opening c, whereby the fluid reserved in container body a can be fed through the front barrel f and dispensed from ejection opening c to applying surface d. When it is not used, ejection opening c is closed.
When the fluid is applied to an applied object, the tip of the valve member is abutted against the applied object so as to set back the valve member into the tubular member, whereby the fluid is flowed out through the clearance around the valve member in the ejection opening.
In the fluid feeder of the above applicator, in order to prevent accidental ejection of the fluid, the applying part at the front end is formed with a sealing element (O-ring) for sealing the applying part and the applying part is urged from the rear by a spring to achieve sealing.
In another applicator of Japanese Patent Publication HEI 08-24885 (patent document 2), the tip is provided with a valve element and a soft elastic part disposed behind the valve element, and a spring is disposed at the rearmost end to urge the valve element forwards to thereby achieve sealing.
In another applicator of Japanese Patent Application Laid-open 2006-346975 (patent document 3), the applicator tip is constructed such that a valve element is set with a sealing element and the rear end of the valve element is urged forwards by a spring to achieve sealing.
In a fluid ejector of Japanese Utility Model Publication HEI 08-10395 (patent document 4), a valve element is pressed by a spring so that the pressurized liquid is ejected from an ejection opening. The valve element is prevented from drying by a resin coating.
However, in any of the technologies disclosed in the above patent documents 1 to 3, when a high-viscosity fluid is ejected, only a lower amount can be ejected, and if the applicator has not been used for a long time, it is difficult to restore its original condition when the fluid is resumed to be ejected. Accordingly, there occurs the problem that the fluid becomes unable to be ejected even if the applicator is halfway through its life.
Additionally, in the description of patent document 4, because the space between the valve seat part of the tubular body and the valve element will not change in volume, it is impossible to secure sufficient flow passage when the fluid in the front end tip is pressurized. As a result, the fluid is unlikely to flow into the space between the valve seat part and the valve element tip, hence the fluid cannot be ejected sufficiently under imperfect pressurization of the fluid. The insufficient ejection causes the problem that the high-viscosity fluid is likely to dry up and harden, resulting in low application performance.
Patent document 1:
Utility Model Application Laid-open HEI 07-24472
Patent document 2:
Japanese Patent Publication HEI 08-24885
Patent document 3:
Japanese Patent Application Laid-open 2006-346975
Patent document 4:
Japanese Utility Model Publication HEI 08-10395